Technology Spotlight: Aerogel Insulation

Synthetic, porous  material derived from a gel, in which the liquid component of the gel has been replaced with a gas, Aerogels are the world’s lightest solid materials, composed of up to 97% air by volume.

Transparent superinsulating silica aerogels exhibit the lowest thermal conductivity of any solid known. The solids in silica aerogels consist of very small, three-dimensional, intertwined clusters that comprise only 3% of the volume. Conduction through the solid is therefore very low. The remaining 97% of the volume of aerogels is composed of air in extremely small nanopores. The air has little room to move, inhibiting both convection and gas-phase conduction.

These properties account for the incredible effectiveness of aerogels as having an extremely low thermal conductivity: from 0.03 W/(m·K) in atmospheric pressure down to 0.004 W/(m·K) in modest vacuum, which correspond to R-values of 14 to 105 (US customary) or 3.0 to 22.2 (metric) for 3.5 in (89 mm) thickness.

For many years, aerogels had been relegated the lab curiosity status and used only in the highly specialized applications. For example, NASA used an aerogel to trap space dust particles aboard the Stardust spacecraft. The particles vaporize on impact with solids and pass through gases, but can be trapped in aerogels. NASA also used aerogel for thermal insulation of the Mars Rover and space suits.

Despite their unique properties, the commercial applications of aerogels were limited. However, over the last two decades, Aspen, the company that initially developed the flexible aerogel blanket insulation used in NASAs space suits, led the way in commercializing silica aerogel blanket material for broader thermal insulation applications.  By 2004, aerogel materials were being used in products selected for use by the Special Forces of the US Military, and the Canadian Ski Team. Shortly thereafter, aerogel insulation blanket materials aimed at industrial, energy, cryogenic and subsea applications appeared on the market.

In 2004, about US$25 million of aerogel insulation products were sold globally. Since then the market has grown substantially to approximately US$500 million today. Continued growth is expected as the potential to replace conventional insulation with aerogel solutions in the building and industrial insulation sectors is significant.

InsulTech is constantly monitoring developments in materials science and recognized early the potential of aerogels. InsulTech has developed engineering and manufacturing capabilities to utilize aerogel materials in thermal insulation blankets for industrial, energy, marine and aerospace applications.

Insultech Earns SOLAS Approval

IMO_fe6c6_450x450 2Insultech has successfully obtained SOLAS approval for several thermal insulation products utilized in marine power and propulsion system applications.

SOLAS, which is an acronym for the International Marine Organization’s International Convention on Safety of Life At Sea, is an international treaty concerning the safety of merchant ships. The convention includes technical standards for ship construction, as well machinery and electrical installations. The requirements are designed to ensure that services which are essential for the safety of the ship, passengers and crew are maintained under various emergency conditions. It also includes stringent fire protection, detection and suppression requirements.

Insultech’s SOLAS approved insulation product portfolio includes soft wrap and sheet metal insulation solutions for the C280 marine power reciprocating engine class from Caterpillar, including the new C280-12. In addition, Insultech offers SOLAS approved insulation kits for LM2500 aeroderivative, marine gas turbine from GE Energy.

“We are excited to expand our share in the marine insulation market”, remarked Tom Bercaw, Insultech’s President. “By enhancing our capabilities to support SOLAS testing and documentation requirements, we are now able to provide our clients an unprecedented level of flexibility and service.”

GenSet Sound Attenuation Basics

Generator sets, especially those installed in or near areas where people live or work, are often subject to specific noise control requirements to minimize impact to human health or quality of life. In the US, for example, The Occupational Safety and Health Administration’s (OSHA’s) Noise standard (29 CFR 1910.95) requires employers to have a hearing conservation program in place if workers are exposed to a time-weighted average (TWA) noise level of 85 decibels (dBA) or higher over an 8-hour work shift. 85 dBA is approximately as loud as the average lawnmower.  Equipment installed in residential areas is often subject to more rigorous requirements, some as low as 70 dBA which is about as loud as the average dishwasher, or even lower.  

Noise Control Policy

Most cities have ordinances regarding the maximum permissible sound levels in given locations. This is straightforward for base load systems, but it is sometimes unclear how a standby generator set, which runs one hour a month for maintenance or during the occasional power outage is defined as a noise source. It is best to check with with the local government to learn how the laws are perceived in a given jurisdiction before finalizing noise control strategies.

Noise Control Enforcement

Various authorities at the national, regional and municipal levels enforce noise control guidelines and limits. Though noise control has been typically regulated at the state and local level, a growing trend is that noise guidelines are becoming more frequently enforced under the US EPA’s Noise Control Act of 1972 and the Quiet Communities Act of 1978. Though the EPA’s funding to enforce these statutes was eliminated in 1982, the laws were never rescinded.

The chart below shows the effects of prolonged exposure for different noise levels.



A number of standards exist for the measurement and calculation of SPL, SWL and other more complex acoustical parameters. ISO standard 8528-10, Measurement of Airbone Noise, by the Enveloping Surface Method, can be referenced as a standard procedure for determining overall SPL readings. A sound level meter (decibel meter) is the most common instrument used in measuring noise sources. A sound level meter works by using a microphone to sense sound pressure, and electronic circuitry to convert sound pressure to an SPL reading.  Other measurement options include real-time sound analyzers and sound intensity probes.

Genset Sound Attenuation Strategies

enclosureOne of the most effective strategies for meeting a genset noise requirement is optimizing the site layout for noise. For example, if the requirement is be lower than 70 dBA at the property line, then sometimes the requirement can be met relatively easily if the genset is located in an area with natural obstructions. Buildings, trees and earth slopes can affect the amount of noise present at a particular measurement point.

In addition, common noise attenuation options on genset packages include acoustic enclosures. These enclosures are typically steel and incorporate sound panels into the walls, roof, and doors. The sound panels typically incorporate fiberglass or mineral wool insulation to increase insertion losses. Acoustic genset enclosures come in a variety of configurations, including “drop-on” enclosures that mount onto the genset skid to minimize footprint, and “drop-over” enclosures that mount directly to the pad. Though “drop-over” enclosures typically perform better from an acoustic perspective, the reduced footprint of a “drop-on” enclosure is sometimes a necessity. Acoustic skid cladding, incorporating insulation, can be added to the skid of “drop-on” enclosures to further reduce emitted noise.

Moreover, most genset packages include silencers on air intake and exhaust systems. These silencers work via one or a combination of 3 device types:

  • Reactive silencers, often referred to as “chamber” silencers;
  • Absorptive silencers, often referred to as “packed” silencers, and
  • Resonators, which are sections of exhaust pipe that expand to a larger diameter and allow the sound waves to reflect off the walls and cancel out.

Sound Insulation Blankets & Curtains

install6Gensets and other industrial machinery are often equipped with sound blankets or curtains. In some cases these blankets are used in lieu of an enclosure, but they can also be used together. For example, custom genset sound blankets can be fitted to the outside of high-heat areas of the genset package such as the exhaust bellows, silencer and stack to further enhance noise absorption. They can also be fitted to the genset machinery itself and have been shown to reduce noise by up to 40 dBA depending on the frequency. These blankets are completely removable and reusable, easy to install and are capable of being used in high temperature applications.

Insultech Attends WTUI in Palm Springs

This week1547da37-a7af-43ac-811e-249cc3931bfb-large, InsulTech’s CEO, Tom Bercaw, attended the 2016 Western Turbine Users, Inc. annual conference in Palm Springs, California.

WTUI is a membership organization of GE LM2500, LM5000, LM6000, and LMS100 users, manufacturers, and suppliers.

The conference was attennce included the annual market outlook presentation from Axford Turbine Consultants’ President, Mark Axford. Key aspects of this presentation strong expected growth in several key gas turbine markets, including Mexico and Egypt and increased market share capture by Siemens in the heavy frame gas turbine class.ded by operators from over 80 power plant facilities, and the expo included more than 100 suppliers.

Highlights of the 2016 conference included the annual market outlook presentation from Axford Turbine Consultants’ President, Mark Axford. Key aspects of this presentation strong expected growth in several key gas turbine markets, including Mexico and Egypt and increased market share capture by Siemens in the heavy frame gas turbine class.